When to conduct a telephone survey using internal resources: You may want to
conduct telephone interviews using internal resources if you have access to a phone
bank (at least 10 to 15 phone lines that can be dedicated to conducting the telephone
survey); a large number of staff members or volunteers, preferably with adequate
skill and training, as well as characteristics that would predispose them to being good
interviewers; and the time to devote to interviewing (which can include contacting
potential respondents multiple times before completing an interview).